1. Field of the Invention
The present invention relates to a method of enhancing pinocytosis of immunoglobulins in postnatal domestic mammals (e.g., bovine).
2. Description of the Related Art
An immunoglobulin is a protein, which has a role in eliminating pathogenic microbes and is essential to mammals. In particular, postnatal calves cannot produce immunoglobulins on their own and cannot protect themselves from infectious diseases without intaking immunoglobulins from the outside sources. Since the first milking colostrum secreted post-parturition by maternal cows contains a high concentration of immunoglobulins, calves normally acquire immunoglobulins by ingestion of such colostrum. However, the absorption capacity of immunoglobulins (pinocytosis) in the small intestines of calves decreases as a function of time post-parturition and almost comes to a nil within 24 hours post-parturition. Because of this phenomenon, the absorption of immunoglobulins is normally accomplished by earlier administration of colostrum to postnatal calves. In this regard, the important points in administering colostrum are as follows: (1) the timing of administering colostrum, (2) the administration amount of colostrum, and (3) the quality of colostrum. As to these conditions, they are described in detail in “Management of Colostrum,” Journal of Clinical Veterinary Medicine, Vol. 19, No. 3 (2001), pp. 18-38. However, there is no method of enhancing pinocytosis efficiecy in postnatal mammals until now.
However, there are many cases in which the above supply conditions cannot be met on account of various reasons. For example, there may be cases of an insufficient amount of colostrum for primiparous cows or an insufficient amount of immunoglobulins in colostrum. The absorption capacity of immunoglobulins in calves may change due to stress or temperature. For these reasons, it cannot be said that the amount of absorption of immunoglobulins in postnatal domestic mammals is sufficient under these circumstances, and the rate of occurrences of infectious diseases in immature calves and the attrition rate have not come down to the satisfactory levels. Accordingly, in order to further enhance resistance of calves against infectious diseases, there remains a need for enhancing absorption capacity of immunoglobulins (pinocytosis efficiency) in postnatal domestic mammals such as calves.